I guess it's akin to the white guy driving through the black neighborhood and automatically locking their car doors.
I dunno...
To be honest, I guess if you live out in the middle of nowhere and you never have to deal with people, you will be more afraid that people in general, will do something shitty to you.
It's just lack of human interaction.
I got a friend of mine who lives in what may be the least crime area of the city and he is always afraid that his SUV is going to get stolen, even though there is virtually no crime in his area at all.